The, you should excuse the expression, literal meaning of peruse is to read or examine closely. It has come to mean its opposite-- to scan, or quickly glance over. Linguistic drift creates ambiguity, and erodes precision in communication. I'm not (quite) the sort of character that goes around chiding people for their language lapses, but when there are useful words or phrases that change their meanings like these examples it is grating upon the ear at best, and confusing at worst. Begs the Question Abuse makes me stop listening in order to puzzle out where the faulty logic might be in the statement.

Well...if the vast majority of English speakers come to use 'peruse' to mean precisely the opposite of its original dictionary meaning, then for them, there's no ambiguity at all. Nor is there a lack of precision in communication for those people. Words aren't invented from whole cloth to mean specific things; language is a messy affair, and though it can be inconvenient, precision in language is often much harder to come by than we might otherwise expect. (Especially in a term like "begs the question", which just by the very words making it up seems to suggest the very meaning that most people now use it for...which makes me think that the original ambiguity was caused BY the original expression, and not imposed on it after the fact by people who didn't know what it really meant.)